This invention relates to rotating data recording devices and more particularly to a self-shielding linear motor actuator for moving transducing heads from one data track to another.
A linear motor for driving magnetic heads from one track position to another of a rotating data storage device must have low mass, high efficiency and good dynamic response. Additionally, it is desirable that such a device be simple, reliable and inexpensive to produce. Voice coil type motors have been widely used for this purpose since such devices meet the stated requirements. Such units employ strong permanent magnets and excitation of the coil produces strong AC flux fields which are inherently incompatible with the magnetic data storage function involving minute magnetic data storage domains on the media which enable the read/write heads to generate currents in the micro ampere range.
As data densities increase with a reduction in the size of the magnetic domains and the magnitude of the generated signal, it becomes increasingly more important that the device be not only more accurate and precise in operation, but also that stray flux fields and the presence of magnetic particulate matter be eliminated. The problem and conditions are further aggravated by the desire to reduce device size and thereby place the component parts in even closer proximity.